Uninitialized scalar field

The field will contain an arbitrary value left over from earlier computations. A scalar field is not initialized by the constructor
/src/mongo/db/pipeline/window_function/window_function_exec_removable_document.h:80: UNINIT_CTOR 120115 Class member declaration for "_lowerBound".
/src/mongo/db/pipeline/window_function/window_function_exec_removable_document.cpp:70: UNINIT_CTOR 120115 Non-static class member "_lowerBound" is not initialized in this constructor nor in any functions that it calls.